A digitally modulated signal for mobile telephony, in particular for GSM, usually consists of individual transmission blocks (bursts) which are modulated by an in-phase component I and a complementary-phase component Q. The modulation is carried out, for example, as 8 PSK.
When measuring the power of such a signal, the problem arises that the power measured within the measurement interval is dependent on the modulation data. However, it is in fact the average long-term power averaged over a theoretically infinite time interval which is of interest. In order to find this long-term power, it has hitherto been customary to measure a very large number of transmission blocks (bursts) and to average the measured signal accordingly. However, this entails relatively long measurement times and is therefore disadvantageous.
There exists therefore a need to provide a method for determining the average long-term power of a digitally modulated signal, which permits measurement in just one transmission block (burst) within a relatively short measurement interval.